苯甲醇在二氧化钛超微粒表面的光诱导电子转移和光反应过程研究

本文用自旋捕捆—ESR方法探讨了苯甲醇在超细微粒二氧化钛胶体表面的光诱导电子转移和光化学行为。结果明确地显示出,在不同pH条件下,笨甲醇在二氧化钛胶体表面的光化学行为有显著差别。在很低pH条件下,体系中检出明显的单重态氧加合物的信号,在pH=3.0左右,则以超氧负离子基为主;pH在4—6范围内时,产生较大量的苄氧基,且认pH=6时为最多;在pH为7左右时,除苄氧基外,同时还有一定量的羟甲基(·CH₂OH)和苯基自由基产生。本文对于不同pH条件下的光诱导电子转移和光化学反应机理进行了讨论。

STUDY OF THE PHOTO-INDUCED ELECTRON TRANSFER AND PHOTOREACTION PROCESS OF BENZYL ALCOHOL ON THE SURFACE OF TiO2 COLLOID

Spin trapping-ESR method was used to study the photo induced electron transfer process of benzyl alcohol on the surface of super fine particles of TiO₂.The results show that at different pH value, there are distinguishing differences about photochemical behaviors of benzyl alcohol on the colloid surface.At very low pH, signals of singlet oxygen were detected clearly.When pH value was about 3.0, super oxide anion dominated.When pH values were raised to 4-6,large amount of benzeloxyl radical was generated, especially when pH=6.When pH was about 7, besides benzeloxyl radical, some hydroxylethyl radical and benzyl radical occured.The photochemical mechanisms of photo-induced electron transfer process under different acidic conditions were discussed.